scholarly journals Influence of fragmentation and disturbance on the potential impact of feral predators on native fauna in Australian forest ecosystems

1996 ◽  
Vol 23 (4) ◽  
pp. 387 ◽  
Author(s):  
S. A. May ◽  
T. W. Norton
Keyword(s):  
Forest Ecosystems ◽  
Prey Species ◽  
Prey Availability ◽  
Current Knowledge ◽  
Native Forest ◽  
Feral Cat ◽  
Predator Prey ◽  
Small Prey ◽  
Potential Impact ◽  
The Impact

The current knowledge is reviewed of the diet and predator–prey relationships of the feral cat (Felis catus), fox (Vulpes vulpes) and dingo (Canis familiaris dingo) (including wild dogs). The effect of forest fragmentation by roads on the use of native forest ecosystems by these species and the significance of this for native fauna is considered. The cat, fox and dingo are significant predators in Australia that interact with native fauna in various ways, including predation, competition for resources, and transmission of disease. On the basis of current knowledge, it is clear that the nature and impact of predation by the cat, fox and dingo on native fauna are primarily determined by prey availability, although there are exceptions to this rule. Generally, dingoes prey upon large to medium-sized prey species (e.g. wallabies, common wombats, and possums), foxes prey upon medium-sized to small prey (e.g. possums and rats) and consume a significant component of scavenged material and vegetation, while cats also prey upon medium-sized to small prey, but may have a greater proportion of reptiles and birds in their diet. The cat is generally considered to be an opportunistic predator and to have contributed to the demise of a number of mammals. The fox is considered more of a threat to small native mammals and it has been asserted that all species of mammals that fall within the critical weight range (CWR) of 120–5000 g are at risk of local extinction when the fox is present. The severity of the impact of the dingo upon the native fauna is considered to be minimal, at least in comparison with the impact that the cat and fox can have on populations. The dingo is not considered a threat to CWR mammals in undisturbed environments. The fox, feral cat and dingo are all considered to have the ability to selectivity prey upon species and, to some extent, individual sexes and age-classes of a number of larger prey species. Although many of Australia's forested areas are relatively heavily fragmented by roads, there are no published studies specifically investigating the use of roads by feral predators. Information on the distribution and abundance of foxes, cats and dingoes in these ecosystems, their ecology and their impact on native fauna is particularly limited. Further, the extent to which roads influence the distribution and abundance of these species and the consequences of these for native fauna are poorly known. One of the most important research needs is to establish the relative impact that exotic predators may have on native fauna under varying degrees of road construction within native forests. For example, are areas with and without roads in forests used differently by exotic predators and what is the significance of this in terms of the potential impact on fauna? The extent to which feral predators forage away from roads needs further investigation, as does the rates of predation within edges, because this may have several consequences for the design, location and size of retained strips and wildlife corridors as well as restoration programmes. Further observations on regional differences influencing predator–prey interactions are required, as is research on the potential impacts on native fauna resulting from prey selection in forests subjected to various degrees of fragmentation and modification.

scholarly journals The impact of large terrestrial carnivores on Pleistocene ecosystems

2015 ◽  
Vol 113 (4) ◽  
pp. 862-867 ◽  
Author(s):  
Blaire Van Valkenburgh ◽  
Matthew W. Hayward ◽  
William J. Ripple ◽  
Carlo Meloro ◽  
V. Louise Roth
Keyword(s):  
Prey Size ◽  
Habitat Degradation ◽  
Terrestrial Ecosystems ◽  
Growth Data ◽  
Predator Prey ◽  
Body Sizes ◽  
Population Sizes ◽  
Potential Impact ◽  
The Impact ◽  
Ground Sloths

Large mammalian terrestrial herbivores, such as elephants, have dramatic effects on the ecosystems they inhabit and at high population densities their environmental impacts can be devastating. Pleistocene terrestrial ecosystems included a much greater diversity of megaherbivores (e.g., mammoths, mastodons, giant ground sloths) and thus a greater potential for widespread habitat degradation if population sizes were not limited. Nevertheless, based on modern observations, it is generally believed that populations of megaherbivores (>800 kg) are largely immune to the effects of predation and this perception has been extended into the Pleistocene. However, as shown here, the species richness of big carnivores was greater in the Pleistocene and many of them were significantly larger than their modern counterparts. Fossil evidence suggests that interspecific competition among carnivores was relatively intense and reveals that some individuals specialized in consuming megaherbivores. To estimate the potential impact of Pleistocene large carnivores, we use both historic and modern data on predator–prey body mass relationships to predict size ranges of their typical and maximum prey when hunting as individuals and in groups. These prey size ranges are then compared with estimates of juvenile and subadult proboscidean body sizes derived from extant elephant growth data. Young proboscideans at their most vulnerable age fall within the predicted prey size ranges of many of the Pleistocene carnivores. Predation on juveniles can have a greater impact on megaherbivores because of their long interbirth intervals, and consequently, we argue that Pleistocene carnivores had the capacity to, and likely did, limit megaherbivore population sizes.

scholarly journals Prey choice and habitat use of people exploiting intertidal resources

2002 ◽  
Vol 29 (2) ◽  
pp. 238-252 ◽  
Author(s):  
W.F. de Boer ◽  
A.-F. Blijdenstein ◽  
F. Longamane
Keyword(s):  
Prey Species ◽  
Prey Availability ◽  
Spring Tide ◽  
Dry Weight ◽  
Intake Rate ◽  
Mangrove Forests ◽  
Prey Choice ◽  
Relative Value ◽  
The Mean ◽  
The Impact

The impact of human exploitation depends mostly on the size of the catch and the species targeted. The value of a species is an important explanatory variable in understanding human impact. Co-management of resources should take into account these different resource values, when evaluating exploitation strategies. The prey choice and foraging behaviour of women and children searching for crabs and shells on the intertidal area at Inhaca Island, South Mozambique, were investigated using optimal foraging theory. This theoretical framework offers the possibility to understand the reasoning of an exploitation strategy and the preference for certain prey species. The number of people was registered, catches were analysed, and timing and substrate choice were recorded. The value of species was estimated using contingency tables. Women were more efficient than children, as their catch was heavier, and the mean weight/animal was larger. The density of women and their timing were positively correlated to prey availability. During neap tide, they spread their visit over more of the low water period and collected crabs by digging in the mangrove forests. No digging occurred during spring tide when a larger area was exposed, the total abundance of species increased, and more species became available. Women then switched to a second strategy, targeting swimming crabs in the tidal channel. Mean neap and spring tide catches were equal (133 g ash-free dry weight per person), but spring catches comprised significantly fewer animals per catch (42 against 123 per person), and mean animal weight was larger (5.4 against 3.0 g ash-free dry-weight per person). Diet breadth was narrower during spring tide, and decreased significantly with increased catch weight. Species with profitabilities (energy intake/handling time) lower than the mean intake rate of 0.024–0.028 g ash-free dry weight s−1 were generally excluded from the diet. The prey preference was positively related to the relative value ranks of the prey species, as measured by ranking of species by women. Women maximized the cumulative relative value ranks during spring tide, instead of total weight. Using this analysis, differences in prey choice and spatial differences in exploitation can be understood as a strategy aimed at maximizing intake and the relative value of a prey species.

scholarly journals Comparing the victimization impact of cybercrime and traditional crime

2021 ◽  
Vol 3 (3) ◽  
pp. 85-110
Author(s):  
Jildau Borwell ◽  
Jurjen Jansen ◽  
Wouter Stol
Keyword(s):  
Law Enforcement ◽  
Literature Review ◽  
Current Knowledge ◽  
Future Research ◽  
Knowledge Gap ◽  
Research Directions ◽  
The Future ◽  
Future Research Directions ◽  
Potential Impact ◽  
The Impact

This paper addresses the importance of building knowledge on the impact of cybercrime victimization. Because the topic is understudied, it is unclear whether the impact of cybercrime differs from that of traditional crime. Our understanding of potential impact differences needs to be improved, considering that society and criminality are digitizing and, consequently, more people are likely to become victims of cybercrime. From a practical perspective, knowledge about the impact of different crimes is important to develop victim policies within law enforcement and other relevant agencies, and to treat victims appropriately. In this paper, a literature review is provided, as well as future research directions to address the current knowledge gap. The future research directions are divided in three topics: (1) distinguishing between cybercrime and traditional crime, (2) classifying cybercrime and traditional crime, and (3) measuring the victimization impact of cybercrime and traditional crime.

Living with the enemy: a threatened prey species coexisting with feral cats on a fox-free island

2020 ◽  
Vol 47 (8) ◽  
pp. 633
Author(s):  
Vivianna Miritis ◽  
Anthony R. Rendall ◽  
Tim S. Doherty ◽  
Amy L. Coetsee ◽  
Euan G. Ritchie
Keyword(s):  
Native Species ◽  
Prey Species ◽  
Occupancy Models ◽  
Feral Cat ◽  
Terrestrial Mammals ◽  
Invasive Predators ◽  
Eastern Australia ◽  
Conservation Actions ◽  
Temporal Interactions ◽  
The Impact

Abstract ContextFeral domestic cats (Felis catus) have contributed to substantial loss of Australian wildlife, particularly small- and medium-sized terrestrial mammals. However, mitigating cat impacts remains challenging. Understanding the factors that facilitate coexistence between native prey and their alien predators could aid better pest management and conservation actions. AimsWe estimated feral cat density, examined the impact of habitat cover on long-nosed potoroos (Potorous tridactylus tridactylus), and assessed the spatial and temporal interactions between cats and potoroos in the ‘Bluegums’ area of French Island, south-eastern Australia. Materials and methodsWe operated 31 camera stations across Bluegums for 99 consecutive nights in each of winter 2018 and summer 2018/19. We used a spatially explicit capture–recapture model to estimate cat density, and two-species single-season occupancy models to assess spatial co-occurrence of cats and potoroos. We assessed the influence of vegetation cover and cat activity on potoroo activity by using a dynamic occupancy model. We also used image timestamps to describe and compare the temporal activities of the two species. Key resultsBluegums had a density of 0.77 cats per km2 across both seasons, although this is a conservative estimate because of the presence of unidentified cats. Cats and long-nosed potoroos were detected at 94% and 77% of camera stations, respectively. Long-nosed potoroo detectability was higher in denser vegetation and this pattern was stronger at sites with high cat activity. Cats and potoroos overlapped in their temporal activity, but their peak activity times differed. Conclusions Feral cat density at Bluegums, French Island, is higher than has been reported for mainland Australian sites, but generally lower than in other islands. Long-nosed potoroos were positively associated with cats, potentially indicating cats tracking potoroos as prey or other prey species that co-occur with potoroos. Temporal activity of each species differed, and potoroos sought more complex habitat, highlighting possible mechanisms potoroos may use to reduce their predation risk when co-occurring with cats. ImplicationsOur study highlighted how predator and prey spatial and temporal interactions, and habitat cover and complexity (ecological refuges), may influence the ability for native prey to coexist with invasive predators. We encourage more consideration and investigation of these factors, with the aim of facilitating more native species to persist with invasive predators or be reintroduced outside of predator-free sanctuaries, exclosures and island safe havens.

scholarly journals A critical review of habitat use by feral cats and key directions for future research and management

2014 ◽  
Vol 41 (5) ◽  
pp. 435 ◽  
Author(s):  
Tim S. Doherty ◽  
Andrew J. Bengsen ◽  
Robert A. Davis
Keyword(s):  
Habitat Use ◽  
Urban Areas ◽  
Prey Availability ◽  
Agricultural Landscapes ◽  
Future Research ◽  
Diverse Range ◽  
Feral Cat ◽  
Feral Cats ◽  
Management Actions ◽  
The Impact

Feral cats (Felis catus) have a wide global distribution and cause significant damage to native fauna. Reducing their impacts requires an understanding of how they use habitat and which parts of the landscape should be the focus of management. We reviewed 27 experimental and observational studies conducted around the world over the last 35 years that aimed to examine habitat use by feral and unowned cats. Our aims were to: (1) summarise the current body of literature on habitat use by feral and unowned cats in the context of applicable ecological theory (i.e. habitat selection, foraging theory); (2) develop testable hypotheses to help fill important knowledge gaps in the current body of knowledge on this topic; and (3) build a conceptual framework that will guide the activities of researchers and managers in reducing feral cat impacts. We found that feral cats exploit a diverse range of habitats including arid deserts, shrublands and grasslands, fragmented agricultural landscapes, urban areas, glacial valleys, equatorial to sub-Antarctic islands and a range of forest and woodland types. Factors invoked to explain habitat use by cats included prey availability, predation/competition, shelter availability and human resource subsidies, but the strength of evidence used to support these assertions was low, with most studies being observational or correlative. We therefore provide a list of key directions that will assist conservation managers and researchers in better understanding and ameliorating the impact of feral cats at a scale appropriate for useful management and research. Future studies will benefit from employing an experimental approach and collecting data on the relative abundance and activity of prey and other predators. This might include landscape-scale experiments where the densities of predators, prey or competitors are manipulated and then the response in cat habitat use is measured. Effective management of feral cat populations could target high-use areas, such as linear features and structurally complex habitat. Since our review shows often-divergent outcomes in the use of the same habitat components and vegetation types worldwide, local knowledge and active monitoring of management actions is essential when deciding on control programs.

scholarly journals Modelling the epidemiology of Escherichia coli ST131 and the impact of interventions on the community and healthcare centres

2016 ◽  
Vol 144 (9) ◽  
pp. 1974-1982 ◽  
Author(s):  
A. TALAMINOS ◽  
L. LÓPEZ-CERERO ◽  
J. CALVILLO ◽  
A. PASCUAL ◽  
L. M. ROA ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Agents ◽  
Current Knowledge ◽  
Epidemiological Studies ◽  
Term Care ◽  
E Coli ◽  
Care Facilities ◽  
Potential Impact ◽  
The Impact

SUMMARYST131 Escherichia coli is an emergent clonal group that has achieved successful worldwide spread through a combination of virulence and antimicrobial resistance. Our aim was to develop a mathematical model, based on current knowledge of the epidemiology of ESBL-producing and non-ESBL-producing ST131 E. coli, to provide a framework enabling a better understanding of its spread within the community, in hospitals and long-term care facilities, and the potential impact of specific interventions on the rates of infection. A model belonging to the SEIS (Susceptible–Exposed–Infected–Susceptible) class of compartmental models, with specific modifications, was developed. Quantification of the model is based on the law of mass preservation, which helps determine the relationships between flows of individuals and different compartments. Quantification is deterministic or probabilistic depending on subpopulation size. The assumptions for the model are based on several developed epidemiological studies. Based on the assumptions of the model, an intervention capable of sustaining a 25% reduction in person-to-person transmission shows a significant reduction in the rate of infections caused by ST131; the impact is higher for non-ESBL-producing ST131 isolates than for ESBL producers. On the other hand, an isolated intervention reducing exposure to antimicrobial agents has much more limited impact on the rate of ST131 infection. Our results suggest that interventions achieving a continuous reduction in the transmission of ST131 in households, nursing homes and hospitals offer the best chance of reducing the burden of the infections caused by these isolates.

scholarly journals A Review on Stems Composition and Their Impact on Wine Quality

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1240 ◽  
Author(s):  
Marie Blackford ◽  
Montaine Comby ◽  
Liming Zeng ◽  
Ágnes Dienes-Nagy ◽  
Gilles Bourdin ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Current Knowledge ◽  
Grape Variety ◽  
Contact Duration ◽  
Wine Quality ◽  
Potential Impact ◽  
The Impact

Often blamed for bringing green aromas and astringency to wines, the use of stems is also empirically known to improve the aromatic complexity and freshness of some wines. Although applied in different wine-growing regions, stems use remains mainly experimental at a cellar level. Few studies have specifically focused on the compounds extracted from stems during fermentation and maceration and their potential impact on the must and wine matrices. We identified current knowledge on stem chemical composition and inventoried the compounds likely to be released during maceration to consider their theoretical impact. In addition, we investigated existing studies that examined the impact of either single stems or whole clusters on the wine quality. Many parameters influence stems’ effect on the wine, especially grape variety, stem state, how stems are incorporated, when they are added, and contact duration. Other rarely considered factors may also have an impact, including vintage and ripening conditions, which could affect the lignification of the stem.

scholarly journals Impact of strawberries on human health: insight into marginally discussed bioactive compounds for the Mediterranean diet

2009 ◽  
Vol 12 (9A) ◽  
pp. 1656-1662 ◽  
Author(s):  
Sara Tulipani ◽  
Bruno Mezzetti ◽  
Maurizio Battino
Keyword(s):  
Human Health ◽  
Current Knowledge ◽  
Potential Health ◽  
Folate Status ◽  
Health Promoting ◽  
Plasma Urate ◽  
Potential Impact ◽  
The Moment ◽  
The Impact

AbstractObjectiveTo review and update the current knowledge on the potential impact of strawberry on human health, with particular attention on compounds and indirect mechanisms of action not exhaustively considered.DesignPersonal perspectives and recent data.SettingInternational.ResultsOur research group was among the few groups that have recently investigated the folate content in fresh, stored and processed strawberries, and the data look very promising. As well, some in vivo evidence of the impact of strawberry intake on the folate status in humans have already been reported, but a new increasing interest on this field is strongly hoped. Furthermore, the hypouricaemic effects previously ascribed to cherry consumption need to be evaluated in respect to strawberry intake. At the moment, inconsistent results come from the few investigations designed at this proposal. In our studies, a great interindividual variability was observed on plasma urate levels in response to strawberry intake, suggesting a putative effect.ConclusionsThe mechanisms responsible for the potential health-promoting effects of strawberry may not be necessarily searched in the activity of phytochemicals. Particularly, a greater interest should be addressed to show whether a prolonged strawberry consumption may effectively improve the folate status and reduce the incidence of folate-related pathological conditions. Furthermore, the hypouricaemic effects of cherries need to be evaluated also in respect to strawberry intake, and the mechanisms of actions and anti-gout potentialities need to be studied in detail.Future investigations involving human trials should be aimed at following these underestimated scientific tracks.

scholarly journals What’s for dinner? Diet and trophic impact of an invasive anuran Hoplobatrachus tigerinus on the Andaman archipelago

2018 ◽  
Author(s):  
Nitya Prakash Mohanty ◽  
John Measey
Keyword(s):  
Prey Availability ◽  
Foraging Strategy ◽  
Amphibian Species ◽  
Predator Prey ◽  
Future Studies ◽  
Hoplobatrachus Tigerinus ◽  
Body Sizes ◽  
Potential Impact ◽  
Trophic Impact ◽  
Ambush Predators

Amphibian invasions have considerable detrimental impacts on recipient ecosystems; however, reliable risk analysis of invasive amphibians still requires research on more non-native amphibian species. An invasive population of the Indian bullfrog, Hoplobatrachus tigerinus, is currently spreading on the Andaman archipelago and may have significant trophic impacts on native anurans through competition and predation. We assessed the diet of the invasive Hoplobatrachus tigerinus (n = 358), the native Limnonectes spp. (n = 375) and Fejervarya spp. (n = 65) in three sites, across four habitat types and two seasons, on the Andaman archipelago. We found a significant dietary overlap of H. tigerinus with Limnonectes spp., which may lead to competition. Small vertebrates, including several endemic species, constituted a majority of H. tigerinus diet by volume, suggesting potential impact by predation. Diets of the three species were mostly governed by the positive relationship between predator-prey body sizes. Niche breadth analyses did not indicate any significant changes in diet between seasons. Hoplobatrachus tigerinus and Fejervarya spp. chose evasive prey, suggesting that these two species are mostly ambush predators; Limnonectes spp. elected sedentary prey; although a large portion of its diet consisted of other prey types, such electivity indicates ‘active search’ as its major foraging strategy. All three species of anurans mostly consumed terrestrial prey. This intensive study on a new genus of invasive amphibian contributes to the knowledge on impacts of amphibian invasions, and elucidates the feeding ecology of H. tigerinus, and species of the genera Limnonectes and Fejervarya. We stress on the necessity to evaluate prey availability and volume in future studies for meaningful insights into diet of amphibians.

Management of invasive mesopredators in the Flinders Ranges, South Australia: effectiveness and implications

2020 ◽  
Vol 47 (8) ◽  
pp. 720
Author(s):  
Alyson M. Stobo-Wilson ◽  
Robert Brandle ◽  
Christopher N. Johnson ◽  
Menna E. Jones
Keyword(s):  
Prey Species ◽  
South Australia ◽  
Short Time Period ◽  
Short Term ◽  
Feral Cat ◽  
Feral Cats ◽  
Flinders Ranges ◽  
Time Period ◽  
Short Time ◽  
The Impact

Abstract ContextSignificant resources have been devoted to the control of introduced mesopredators in Australia. However, the control or removal of one pest species, such as, for example, the red fox (Vulpes vulpes), may inadvertently benefit other invasive species, namely feral cats (Felis catus) and rabbits (Oryctolagus cuniculus), potentially jeopardising native-species recovery. AimsTo (1) investigate the impact of a large-scale, long-term fox-baiting program on the abundance of foxes, feral cats and introduced and native prey species in the Flinders Ranges, South Australia, and (2) determine the effectiveness of a short time period of cat removal in immediately reducing feral cat abundance where foxes are absent. MethodsWe conducted an initial camera-trap survey in fox-baited and unbaited sites in the Flinders Ranges, to quantify the impact of fox baiting on the relative abundance of foxes, feral cats and their prey. We then conducted a secondary survey in sites where foxes were absent, following an intensive, but short, time period of cat removal, in which 40 cats were shot and killed. Key resultsNo foxes were detected within baited sites, but were frequently detected in unbaited sites. We found a corresponding and significant increase in several native prey species in fox-baited sites where foxes were absent. Feral cats and rabbits were also more frequently detected within baited sites, but fox baiting did not singularly predict the abundance of either species. Rather, feral cats were less abundant in open habitat where foxes were present (unbaited), and rabbits were more abundant within one predominantly open-habitat site, where foxes were absent (fox-baited). We found no effect of short-term cat removal in reducing the local abundance of feral cats. In both camera-trap surveys, feral cat detections were positively associated with rabbits. ConclusionsLong-term fox baiting was effective in fox removal and was associated with a greater abundance of native and introduced prey species in the Flinders Ranges. To continue to recover and conserve regional biodiversity, effective cat control is required. ImplicationsOur study showed fox removal has likely resulted in the local release of rabbits and an associated increase in cats. Because feral cat abundance seemingly fluctuated with rabbits, we suggest rabbit control may provide an alternative and more effective means to reduce local feral cat populations than short-term removal programs.

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